Help Turning off after about 20 seconds (inc safe mode)

[ChristoffGp4gP]

To turn on my phone, I have to remove and replace the battery.

After booting to the home screen, it works for about 20 or 30 seconds, freezes, then tries to reboot.

Sometimes, during the freeze, before reboot, a black horizontal line appears on the screen (in no particular place - it seems random).

On rebooting, it never gets past the boot screen/Samsung logo. I have to remove the battery to get further, but it always freezes and turns off after 20 or so seconds.

I've tried booting into safe mode, which works in exactly the same way - it loads the home screen, and then freezes and tries to reboot.

I've previously had an issue with my power button getting stuck, which seems to be a common problem with the S4. However, while this issue seems similar initially (seemingly stuck in a boot loop), I don't think it's the same issue, as when it gets to the home screen, it freezes and dies, rather than brings up the power off option (which it used to do when the power button got stuck in the past).

Does anyone have any ideas? Even if it's just a temporary fix to try and back stuff up? 20 seconds isn't long enough to do anything. I need a new phone soon anyway (trying to hold out on the OnePlus 5) but I could really do with backing stuff up - I'm not too worried about saving the phone long term.

Thanks to anyone who can offer any advice.

 

[nu2andy]

Have you taken the inner cover off and blown around the switch (on/off button) ? Dust and dirt can be the cause of your problem.

 

[ChristoffGp4gP]

Thanks for your reply.

I've tried, but have been unable to take off the cover (couldn't get much past unscrewing the screws) - the phone has been damaged in the past (over a year ago) and the person who repaired it did a shoddy job of fixing the screen to the phone (there are visible gaps around some edges) so I was very worried about accidentally ripping the screen off!

Does it sound likely to be a power button issue? Or could there be a software issue? The fact the the phone freezes, a black horizontal line appears, and then gets stuck in a boot loop, suggests to me that it might be a software problem somehow? Or other hardware failing? This stuff never happened when I had the power button issue a few months ago.

Thanks

 

[nu2andy]

I would still suggest the switch is causing the problem.
https://www.ifixit.com/Teardown/Samsung+Galaxy+S4+Teardown/13947
Have a look through the Steps shown in this link.
Step 5 shows NO gaps around the frame to screen. If there are gaps - it suggests to me that it is a bad fit up, or parts are jammed under the cover such as an antenna cable.
Step 8 Shows the tool suggested to release the frame cover.
I have dismantled and refurbished at least 6 S4 phones. I purchase new digitizer and LCD assemblies if the screen is broken and although it is a dearer job, there is a 100% guarantee that it will be like new again.
I have replaced logic boards and charging circuits and renewed frames and covers which can be bought on the internet. Make sure the battery cover is genuine, as flash jazzy looking battery covers may have metal in them which will affect reception and output.
I have found on a couple of units that the Power switch plate can be distorted/bent and cause the problem that you are experiencing. Likewise the Volume control plate can also be similarly damaged and prevent action to enable Safe Mode or Recovery Mode to be enabled.
These plates can be reshaped and straightened if tweezers are used to carefully remove them from the frame.
To access the switch plates, you need to remove the frame as shown in the pictures/video. You should use only plastic tools as shown as metal tools may do more damage than good. (it's very hard on thumbnails).

 

[ChristoffGp4gP]

Thanks again.

I've taken the phone to a local repair shop and explained the situation.

The guy there took the back off and cleaned the power button area, though didn't do anything with the plates. Unfortunately it didn't fix the issue and he's convinced it's a software issue (I think due to the freezing and horizontal line that appears).

The phone now won't even get to the lock screen, it dies before then, so seems to be getting worse.

It even froze and died in recovery mode when he went into it - something that didn't happen to me when I tried cleaning the cache there the other day - it had previously seemed immune to the problem.

Could there be another piece of hardware failing, that might explain why it seems to be getting worse each time?

 

[nu2andy]

How old is your battery? When the repair guy put the phone back together, is the frame all fitting correctly?

the phone has been damaged in the past (over a year ago) and the person who repaired it did a shoddy job of fixing the screen to the phone (there are visible gaps around some edges)

If the middle frame was replaced with the wrong part, the logic board may not be seating squarely causing distortion when the top cover is screwed down. This may be causing a short/fault in the circuits which may account for the shorter time frame of your failure. If the front cover complete with screen and LCD was renewed and is for the i9500 model, there are subtle differences on the mounting areas and the logic board will not seat properly. When the center frame is clipped down, the misalignment won't allow the frame to clip down evenly - hence the gaps you saw initially.
The fact that the phone won't power on now for more than a few seconds points to break/s in the circuit. Software is very unlikely to be the cause.

 

[ChristoffGp4gP]

Thanks. It's been a while but I didn't want to leave this without updating you after your help.

I took it to another phone repair centre who identified the problem as a short. Unfortunately after many different attempts at fixing it, they were unable to.

So I've given up all hope!

Thanks anyway.